On December 16, 1942, the USS Triton (SS-201), captained by Lieutenant Commander Charles C. Kirkpatrick, departed Pearl Harbor on her fifth war patrol. During the first part of her fifth war patrol Triton would be under the operational control of Commander Task Force Seven. Kirkpatrick’s operation order instructed him to position the Triton twenty miles east of Wake Island to assist in guiding Army B-24 Liberator bombers making a night attack on enemy positions on Wake. The Triton would also rescue any downed Army aviators if necessary. She was in position by December 23rd, acting as a radio beacon. At 2300 hours that night the first wave of Liberators started dropping their bombs. The attacks lasted until 2347 hours. None of the Liberators incurred any damage. At 0528 hours, on December 24, 1942, the Triton stood off Peacock Point on the southeast corner of Wake Island to conduct reconnaissance. At 0712 hours Kirkpatrick sighted two masts of a ship heading slowly into the anchorage south of Wilkes Island. He conned the Triton so she was just south of this ship, which was now at anchor about 1,000 yards south of the Wilkes Island boat landing, and identified it as a "…typical Engines Aft old Tanker" with an estimated tonnage of 7-8,000. A patrol craft escorted a lighter to the tanker and then took up patrol to seaward of Triton. At 0915 hours, from a range of 1,300 yards, Triton fired two torpedoes at the tanker. Both fish hit him and he was completely engulfed by water, smoke, and steam. Just to be sure, Kirkpatrick fired a third torpedo. It hit the tanker amidships and he started going down by the stern. Kirkpatrick then put Triton at 200 feet and turned her to the southeast. Explosions thought to be from aerial bombs were heard astern until about noon; none were close enough to cause any damage. The endorsement to Kirkpatrick’s patrol report credited the Triton for sinking a loaded a tanker of about 7,000 tons; the postwar JANAC assessment, as well as the recent Alden-McDonald evaluation, scored it as a 1913-ton water carrier, the Amakasu Maru #1.
On December 28, 1942, operational control over Triton passed to Commander Task Force Forty Two. Kirkpatrick’s operational order from COMTF42 directed him to patrol in the Truk-Rabaul-New Guinea shipping corridor northwest of New Ireland. While en route to this area, the Triton attacked and sank the 3,394-ton passenger vessel Omi Maru, off Pingelap Atoll. Triton’s patrol in the Truk-Rabaul-New Guinea shipping corridor lasted from December 30, 1942 to January 16, 1943. She was moved to different positions within this area several times as part of Captain James Fife’s “checkers” method for chasing Ultra contacts. She made four additional attacks on enemy shipping in this area. In addition to the two previously cited vessels, Fife’s endorsement credited Triton for sinking a 7,000-ton cargo vessel and damaging two others, a 10,200-ton tanker and a 4,000-ton cargo ship. The JANAC and Alden-McDonald scores credit only the Amakasu Maru #1 and the Omi Maru as having been sunk; the Alden-McDonald score credits the 10,121-ton tanker Akebono Maru as having been damaged.
The Triton arrived at Brisbane at dawn on January 26, 1943. In preparation for her sixth and final patrol, Lieutenant Commander George K. MacKenzie, Jr. relieved Kirkpatrick as the Triton’s commanding officer. Kirkpatrick would move on and later become the commanding officer of the destroyer minelayer USS Shea (DM-30). The Triton would return to the same patrol area on her next war patrol.